21. The compound amount on a certain sum for 1 year
is Rs. 281600 and for 3 years is Rs. 340736. Find
the sum and the rate of interest. (कुनै रकमको चक्रिय
मिश्रधन 1 वर्षमा रु. 281600 र 3 वर्षमा रु. 340736 हुन्छन्
भने उक्त रकम र ब्याजदर पत्ता लगाउनुहोस् ।
Step-by-step explanation:
Sum (p)=Rs.12000
Rate of interest =14% per annum
Time =1 year
Since the interest is compounded half yeary.
Therefore,
R=
2
14
=7%
n=2
Therefore,
A=P(1+
100
R
)
n
⇒A=12000(1+
100
7
)
2
⇒A=
100×100
12000×107×107
=Rs.13738.8
Therefore,
Compound interest =A−P
=13738.8−12000
=Rs.1738.8